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   难度：Medium
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  <div>
   <h1 class="question_title">
    1048. Clumsy Factorial
   </h1>
   <p>
    Normally, the factorial of a positive integer
    <code>
     n
    </code>
    &nbsp;is the product of all positive integers less than or equal to
    <code>
     n
    </code>
    .&nbsp; For example,
    <code>
     factorial(10) = 10 * 9 * 8 * 7 * 6 * 5 * 4 * 3 * 2 * 1
    </code>
    .
   </p>
   <p>
    We instead make a
    <em>
     clumsy factorial:
    </em>
    &nbsp;using the integers in decreasing order, we&nbsp;swap out the multiply operations for a fixed rotation of operations:&nbsp;multiply (*), divide (/), add (+) and subtract (-) in this order.
   </p>
   <p>
    For example,
    <code>
     clumsy(10) = 10 * 9 / 8 + 7 - 6 * 5 / 4 + 3 - 2 * 1
    </code>
    .&nbsp; However, these operations are still applied using the usual order of operations of arithmetic: we do all multiplication and division steps before any addition or subtraction steps, and multiplication and division steps are processed left to right.
   </p>
   <p>
    Additionally, the division that we use is
    <em>
     floor division
    </em>
    &nbsp;such that&nbsp;
    <code>
     10 * 9 / 8
    </code>
    &nbsp;equals&nbsp;
    <code>
     11
    </code>
    .&nbsp; This guarantees the result is&nbsp;an integer.
   </p>
   <p>
    <code>
     <font face="sans-serif, Arial, Verdana, Trebuchet MS">
      Implement the&nbsp;
     </font>
     clumsy
    </code>
    &nbsp;function&nbsp;as defined above: given an integer
    <code>
     N
    </code>
    , it returns the clumsy factorial of
    <code>
     N
    </code>
    .
   </p>
   <p>
    &nbsp;
   </p>
   <p>
    <strong>
     Example 1:
    </strong>
   </p>
   <pre>
<strong>Input: </strong>4
<strong>Output:</strong>&nbsp;7
<strong>Explanation:</strong> 7 = 4 * 3 / 2 + 1
</pre>
   <p>
    <strong>
     Example 2:
    </strong>
   </p>
   <pre>
<strong>Input: </strong><span id="example-input-1-1">10
</span><strong>Output: </strong><span id="example-output-1">12
</span><strong>Explanation: </strong>12 = 10 * 9 / 8 + 7 - 6 * 5 / 4 + 3 - 2 * 1
</pre>
   <p>
    &nbsp;
   </p>
   <p>
    <strong>
     Note:
    </strong>
   </p>
   <ol>
    <li>
     <code>
      1 &lt;= N &lt;= 10000
     </code>
    </li>
    <li>
     <code>
      -2^31 &lt;= answer &lt;= 2^31 - 1
     </code>
     &nbsp; (The answer is guaranteed to fit within a 32-bit integer.)
    </li>
   </ol>
  </div>
  <div>
   <h1 class="question_title">
    1048. 笨阶乘
   </h1>
   <p>
    通常，正整数
    <code>
     n
    </code>
    的阶乘是所有小于或等于
    <code>
     n
    </code>
    的正整数的乘积。例如，
    <code>
     factorial(10) = 10 * 9 * 8 * 7 * 6 * 5 * 4 * 3 * 2 * 1
    </code>
    。
   </p>
   <p>
    相反，我们设计了一个笨阶乘
    <code>
     clumsy
    </code>
    ：在整数的递减序列中，我们以一个固定顺序的操作符序列来依次替换原有的乘法操作符：乘法(*)，除法(/)，加法(+)和减法(-)。
   </p>
   <p>
    例如，
    <code>
     clumsy(10) = 10 * 9 / 8 + 7 - 6 * 5 / 4 + 3 - 2 * 1
    </code>
    。然而，这些运算仍然使用通常的算术运算顺序：我们在任何加、减步骤之前执行所有的乘法和除法步骤，并且按从左到右处理乘法和除法步骤。
   </p>
   <p>
    另外，我们使用的除法是地板除法（
    <em>
     floor division
    </em>
    ），所以&nbsp;
    <code>
     10 * 9 / 8
    </code>
    &nbsp;等于&nbsp;
    <code>
     11
    </code>
    。这保证结果是一个整数。
   </p>
   <p>
    实现上面定义的笨函数：给定一个整数
    <code>
     N
    </code>
    ，它返回
    <code>
     N
    </code>
    的笨阶乘。
   </p>
   <p>
    &nbsp;
   </p>
   <p>
    <strong>
     示例 1：
    </strong>
   </p>
   <pre><strong>输入：</strong>4
<strong>输出：</strong>7
<strong>解释：</strong>7 = 4 * 3 / 2 + 1
</pre>
   <p>
    <strong>
     示例 2：
    </strong>
   </p>
   <pre><strong>输入：</strong>10
<strong>输出：</strong>12
<strong>解释：</strong>12 = 10 * 9 / 8 + 7 - 6 * 5 / 4 + 3 - 2 * 1
</pre>
   <p>
    &nbsp;
   </p>
   <p>
    <strong>
     提示：
    </strong>
   </p>
   <ol>
    <li>
     <code>
      1 &lt;= N &lt;= 10000
     </code>
    </li>
    <li>
     <code>
      -2^31 &lt;= answer &lt;= 2^31 - 1
     </code>
     &nbsp; （答案保证符合 32 位整数。）
    </li>
   </ol>
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